(i) Field of the Invention
The present invention relates to a liquid detergent composition having excellent foamability, detergency, stability at low temperatures and a low viscosity.
(ii) Description of the Prior Art
A liquid detergent such as an detergent for tablewares desireably satisfy the property requirements of superior detergency, foamability, and low irritativeness to the skin. In order to fulfill these requirements, an anionic surface active agent and a non-ionic surface active agent have been used as the chief ingredients to prepare a liquid detergent. Among the non-ionic surface active agents, a tertiary amine oxide has been known as an agent which produces an excellent effect (see Japanese Patent Specification Nos. 14979/1964 and 3264/1963).
However, a combined use of tertiary amine oxide and anionic surface active agent in preparing a liquid detergent generally gives disadvantages of reduced stability at low temperatures and raised viscosity. In order to prevent such disadvantages, ethanol or paratoluenesulfonate has been additionally incorporated. However, an incorporation with a small quantity thereof does not reveal any effect, whereas an incorporation with a large quantity thereof incurs inferior foaming property and inflammable danger.
A certain kind of succinic acid derivative has been used as one of the ingredients of liquid detergents. For example, Japanese Patent Application Laid-Open No. 142603/1975 describes a combined use of a succinic acid derivative represented by the formula: ##STR2## wherein R.sub.4 is a hydrocarbon group having 4-14 carbon atoms, and a lower alcohol, both as the solubilizing agents of a heavy duty detergent. Japanese Patent Publication No. 35330/1973 discribes an addition of a water soluble salt of a succinic acid derivative represented by the formula: ##STR3## wherein R.sub.4 is an alkyl group or alkenyl group containing 10-20 carbon atoms, as a builder substituted for tripolyphosphate. Further, Japanese Patent Application No. 142099/1980 describes a use of a succinic acid derivative represented by the formula: ##STR4## wherein R.sub.4 is a hydrocarbon group having 8-18 carbon atoms as the main active ingredient of a detergent. However, the conventional use of the succinic acid derivative as an ingredient of a detergent is as an adjuvant in co-existence of an alkaline builder, or is as an active ingredient of the detergent.